This invention generally relates to an elevator system. More particularly, this invention relates to an elevator motion alert system for alerting a mechanic working inside an elevator hoistway.
Maintenance and repair of elevator systems may require a mechanic to enter the elevator hoistway. The mechanic may need to work within the pit at the bottom of a hoistway, on top of the elevator car or at an intermediate location within the hoistway between the pit and the overhead. Mechanics may be faced with dangerous situations caused by a moving elevator car and a moving counterweight.
For example, a mechanic working on top of the elevator car must avoid collision with a passing counterweight. When working in the pit, the mechanic must avoid collision with either a car or a counterweight moving downward into the pit. When working in an intermediate location between the pit and the overhead, the mechanic must avoid collision with either a car or a counterweight passing by.
WO 2008/082380 discloses a warning system for mechanics working inside an elevator hoistway which senses elevator cab position within the hoistway and senses the presence of the mechanic. A mechanic will receive a voice-based warning message of approaching danger based upon the sensed elevator and mechanic positions. US 2017/137256 A1 discloses an elevator motion alert system configured to alert mechanics working inside an elevator hoistway which detects motion of an elevator car or counterweight and broadcasts a pressure wave indicative of elevator car or counterweight motion. An electronic device receives the pressure wave and alerts the mechanic.
In these prior art systems, various devices for sensing and communicating the position or motion of the elevator car, counterweight and/or mechanic are necessary and power supplies and wiring for signal communication are required. Installation of such devices in existing elevator systems would require additional costs and time since rewiring would be necessary. Further, the location of such devices would be limited.
In view of the above and other considerations, there is a need for providing an elevator motion alert system for alerting a mechanic working in an elevator hoistway which is easy to install in existing elevators.